Hello I have a 17.5 blazer it is a 1988 model had a 150 mercury xr4 boat will run 72mph then it starts to loose control took the 150 0ff put a 1989 mercury 225 the boat will run 70mph with lots of petal left but the boat starts to loose control played with jackplate from top to bottom have a quicksilver 25p on now had a 27p chopper same results is 70mph all this boat will go even with more power? only rides smoth at 65mph.any help?